Coal cutting machine



Dec. 20, 1932. D, LEVlN 1,891,562

GOAL CUTTING MACHINE Original Filed Nov. 1, 1928 3 Sheets-Sheet 1 1329.r Fi 8 3mm 477933 O alltoimzwv 20, 1932- N. b. LEVIN 1,891,562

GOAL CUTTING MACHINE Original Filed Nov. 1, 1928 {5 Sheets-Sheet 5Patented Dec. 20, 1932 UNITED STATES PATENT OFFICE' NILS D. LEVIN, O1WLUHBUS, OHIO, ASSIGNOB TO THE JEFFREY MANUFACTURING comm, OF OOLUHBU'S,OHIO, CORPORATION OF OHIO con. ou'r'rme micnmn Application filedNovember 1, 1928, Serial No. 818,585. Renewed October 7, 1931.

The resent invention relates to certain new an useful improvements incoal cuttin machines, and particularly to machines the class comprisinga frame adapted to rest upon and slide in any direction over the minefloor, a kerf cutter projecting horizontally therefrom, winding devicesmounted upon the main frame and flexible draft devices attached to andwindable upon said winding devices adapted to cooperate with anchoringdevices external of the machine to move and guide it relative to thematerial to be mined.

It is the especial object of this invention to rovide, in a machine ofthe class descri d, an improved arrangement of parts whereby theexternal dimension of the machine may be reduced without impairment ofthe efliciency, strength or durability of the machine.

The means whereby I attain these and other objects are fully set forthin the following specification and illustrated in the accompanyingdrawings of which Fig. 1 is a plan view of the preferred embodiment'ofmy invention.

Fig. 2 is a side elevation of the machine illustrated in Fig. 1.

Fig. 3 is a fragmentary plan view of the rearward part of the machineillustrated in Figs. 1 and 2, certain parts being broken away to revealother parts.

Fig. 4 is a sectional view taken along the line IV-IV of Fig. 3.

Fig. 5 is a sectional view taken along the line V-V of Fig. 3.

Fig. 6 is a rear elevation of the machine illustrated in Figs. 1 and 2,the cover plate being removed to reveal the feed controlling mechanism.

Fig. 7 is a view taken along the line VII VII of Fig. 3.

Fig. 8 is a sectional view taken along the line VIIIVIII of Fig. 3.

Figs. 9, 10 and 11 are diagrams illustrating chine.

Like numerals refer to similar parts in the several figures.

' As shown in -the drawings the preferred some of the methods ofoperating the maembodiment of my invention comprises a main frameadapted to rest u n and slide in any direction over the floor o themine, upon which the operative parts of the machine are supported. Ashere shown this main frame comprises three sections 1, 2 and 3, securelyoined together by suitable bolts. The central section 2 consists of asingle steel casting which constitutes the magnetic frame of an electricmotor having a longitudinally extending armature 4 whereby the machineis actuated. The casting. 2 also contains chambers wherein are mounteddevices for the control of the actuation of the motor. Electriccurrent'for the actuation of this motor may be derived from anyconvenient source in any convenient manner but as such devices are wellunderstood in the mining machine art, and as they form no part-in thepresent invention, their illustration and description is not thought tobe required at this time. Rigidly secured to the forward frame section 1and projecting horizontally therefrom is a cutter frame 5 havingguideways formed in its lateral edges wherein travels the endless cutterchain 6 to which are attached the cutter bits 7 adapted to engage thecoal to cut it. The chain 6 passes around andis actuated by a sprocketwheel 8 fixed to a vertical shaft 9 mounted in suitable bearings of theframe section 1, and is operatively connected with the armature shaft 4of the motor bythe bevel gears 10 and 11.

The rearward frame section 3 is built up of three castings 12, 13 and14, securely joined together and to the motor frame 2 by suitableattachment bolts 15, and in the frame thus formed is mounted the feedingand guiding mechanism. The feeding and guiding mechanism comprises twowinding drums 16 and 17 upon which are windable the feed ropes 18 and 19adapted to cooperate with suitable abutments external of the machine.The drums 16 and 17 are mounted to revolve about vertical axessymmetrically positioned one at either side of the longitudinal centerline of the machine. Since the winding drums 16 and 17 and theiractuating mechanisms are alike, a description of one will apply to both.

The drum 17 is mounted to revolve freely upon a hub 20 which, in turn,is eccentrically rotatable about a stationary shaft 21 fixed to 'theframe of the machine. The hub 20 is provided with an arm 22 projectinghorizontally to a position convenient to the hand of the operator.Formed on the inner face of the drum 17 are internal gear teeth adaptedto engage the teeth of a pinion 23 formed integral with a vertical shaft24 which is journaled in a bearing 25 formed in the casting 13 of themachine frame. The shaft 24 is operatively connected with the armatureshaft 4 of the motor through a train of gearing comprising a planetarygear system which incorporates mechanism whereby the actuation of thedrum 17 may be controlled. Keyed to the upper end of the shaft 24 is awheel 26 the hub 27 of which forms a journal for the shaft 24 in thebearing 28 of the top casting 14 of the machine frame. The wheel 26 isprovided with a downwardly projecting annular flange 29 having on itsinner face gear teeth which engage the teeth of a plurality of pinions30. The pinions 30 are freely rotatable upon stud shafts 31 fixed to thespider 32. The spider 32 has inwardly projecting bearing elements 33engaging a bearing surface formed on the hub 27 of the wheel 26 tomaintain said spider in concentric relation with the shaft 24. Otherpinions 34 are formed integral with the pinions 30, and these pinions 34engage a spur gear 35 fixed to the hub of the worm wheel 36 which isfreely rotatable about the shaft 24. The worm wheel 36 engages a worm 37formed integral with the worm'shaft 38. and this worm shaft is supportedin journal bearings 39 and 40 of the frame casting 13, which arepositioned in the central longitudinal vertical plane of p the machinecoaxial with the armature shaft 4 to which the shaft 38 is connected bya shaft coupling 41. An annular flange 42 formed on the spider 32 isembraced by a brake band 43 engagement of which resists rotation of thespider 32. A second ring gear 44 supported by, but freely movablerelative to the spider 32 engages the pinions 34, and this second ringgear 44 is embraced by a second brake band 45 whereby its rotation maybe resisted.

The brake bands 43 and 45 are preferably formed of spring steel, orother suitable material having a relatively high coeflicient ofelasticity. and they are preferably lined with fibrous material, asshown at 46 in Fig. 4, to provide a suitable coefiicient of friction.

' The said brake bands are formed with a curvature of somewhat greaterdiameter than the cylindrical surfaces which they embrace, and tend tospring away from said surfaces. lug 47 fixed to one end of the brakeband 45 engages the abutment 48 formed on the machine frame. and asimilar lug 49 fixed to the other end of the same brake band engages afinger 50 which projects upwardly from a feed nut 51. Similar lugs 52'and 53 attached to the brakeband 43 engage the abutment 54 of themachine frame, and the downwardly projecting finger 55 of the feed nut51 respectively. The arrangement of these parts is such that movement ofthe nut 51 toward the right tightens the up er brake band 45 andreleases the lower br e band 43 while movement of the said ,nut 51toward the left tightens the lower brake band 43 and loosens the upperbrake band 45. The brake band 45 is supported by the lugs 47 and49xresting upon the upper surface of the feed nut 51 and a lug 57attached to the middle of the brake band 45 engages. a flange58 of themachine frame. The brake band 43 is similarly supported, the lugs 52 and53 resting upon a surface 59 of the machine frame.

The planetary system associated with the drum 16' is similar to thatabove described, and because the worm wheel 60 engages the worm 37opposite to the worm wheel 30 the drum 16 will be driven in clockwisedirection when the drum 17 is driven anti-clockwise. The brake bands 61and 62 are similar to those above described having similar In 63 and 64engagin abutments 65 and 66 of t e frame, and lugs 6 and 68 engaging thefingers 69 and 70 of the feed nut 71.

The feed nut 71 is slidablysupported ina guideway 72 formed in themachine frame, and is screw threaded to a shaft 73 whichextendstransversely of the machine. A flange 74 formed integral with the shaft73, and a' collar 75 screw threaded thereto engage opposite sides of athrust collar 76 seated ina suitable recess of the machine frame whichacts to prevent longitudinal movement of the shaft 7 3 in eitherdirection. Fixed to .the other end of the shaft 73. isa spur gear 77which engages a similar gear 78 formed one. cylindrical sleeve 79 whichprojects through the machine frame and is journaled in a hearing 80thereof. On the outer end of the sleeve 79 is formed a hand wheel 81positioned convenient to the hand of the operator, by manipulation ofwhich the shaft 73'may be rotated in either direction to causelongitudinal movement of the nut 71 in the guideway 72. The feed nut 51is slidable in a 'deway 82 formed in the machine frame, an is screwthreaded to a sleeve 83 which is mounted concentrically of the shaft 73and adapted to rotate relative thereto. A flange-84 formed integral withthe sleeve 83, and a collar 85 screw threaded thereto, engageoppositesides of a thrust collar 86 which is seated in a suitable recessof the machine frame and acts to prevent longitudinal movement of saidsleeve A in either direction. A spur gear 87 formed integral with thethrust collar 85 engages a similar gear 88 fixed to the shaft 89. Theshaft 89 is rotatably mounted in the sleeve 79 and to its projecting endis attached a second hand wheel 90 by the manipulation of which thesleeve 83 may be rotated to move the feed nut 51 longitudinally in itsguideways. The guideways 72 and 82, and the recesses for the thrustcollars 76 and 86 are open rearwardly of the machine to facllitate theinsertion or removal of the shaft 73 and its associated parts, and theseparts are retained in operative position by the cover plates 91 attachedto the frame castings 13 and 14 by suitable bolts.

When. by manipulation of the hand wheel 90, the feed nut 51 is moved tothe left the brake band 43 will be tightened to prevent rotation of thespider 32 thereby causing the vertical shaft 24 to be driven to wind thefeed rope 19 at a relatively fast speed suitable for handling themachine over the mine floor. lVhen the feed nut 51 is similarly moved tothe right, the brake band 45 will be tightened to prevent rotation ofthe ring gear 44, and thereby cause the vertical shaft 24 to' be drivento wind the feed rope 19 at a relatively low speed suitable for feedingthe cutting mechanism into the coal. When the feed nut 51 is in acentral. or neutral, position, both of the brake bands 43 and 15 will bereleased from engagement with their respective driving elements, and theshaft 24 will remain idle. It is apparent that if the brake bands arepartially tightened, permitting a greater or less degree of slippagebetween the brake bands and their respective driving elements, the speedof the shaft 24 will be proportionately reduced, and that these brakebands may act, under such circumstances, to retard rotation of the shaft24 in a reverse direction.

By manipulation of the hand wheel 81 the shaft 92 may be driven inprecisely the same manner as above described to cause the drum 16 towind the feed rope 18 or to permit its unwinding under frictionalcontrol.

In the operation of this machine either of the ropes 18 or 19 may beused at relatively high speed to move the machine into position. Whenthe machine has been suitably placed adjacent the coal face, asillustrated in Fig. 9, the levers 22 may be moved to disengage the drums16 and 17 from their respective driving pinions, permitting the freerotation of the drums. The feedropes 18 and 19 may then be drawn out andattached to the anchors 93 and 94 suitably positioned adjacent the coalface. When now the cutter chain 6 is actuated and the levers 22 restoredto cause engagement of the drums 16 and 17, the hand wheels 81 and maybe manipulated to cause rotation of the drums 16 and 17 to wind bothfeed ropes 18 and 19 at relatively low speed to feed the cutter arm 5longitudinally into the coal.

lVhen the cutter arm 5 has been completely sumped, the lever 22 may beagain moved to release the drum 17, the feed ropes 19 drawn therefrom,passed around the guide sheave 95 at the forward end of the machineframe, and attached to the anchor jack 96 atthe left hand rib adjacentthe coal face, as illustrated in Fig. 10. At thesame time the tail rope18 will be moved to the anchor jack 97 positioned adjacent the righthand rib at a suitable distance from the coal face. I

The hand wheel 90 will now be manipulated to cause rotation of the drum17 in a rope winding direction at feeding speed, and the hand wheel 81manipulated to permit unwinding of the feed rope 18 under frictionalresistance, to feed the cutter arm 5 laterally toward the left hand rib,and to maintain its angular relation with the coal face.

\Vhen it is desired to feed the machine from left to right, afterreversing the cutter bits 7 in the sockets of the cutter chain 6, thedirection of rotation of the armature 4 may be reversed, therebyreversing the direction of travel of the cutter chain 6, and thedirection of rotation of the drums .16 and 17. The feed ropes 18 and 19will then be drawn out completely from their respective drums, re-woundin the opposite direction, and attached to the jacks 98 and 99, asillustrated in Fig. 11, after which the operation will proceed as abovedescribed.

By the arrangement of parts above described, I have produced a coalcutting machine of small vertical dimensions, extreme durability,simplicity of design, and efiiciency of operation. It is to beunderstood, however, that I do not limit myself to the preciseconstruction here shown since the machine may be subject to widevariation as to details without departure from the spirit of myinvention.

What I claim is 1. In a machine of the class described, the combinationwith a frame adapted to rest upon and slide in any direction over thefloor of a mine, of mining mechanism mounted thereon, feeding andguiding mechanism comprising two flexible draft elements adapted tocooperate with anchoring devices external of the machine, two windingdrums mounted for rotation about vertical axes and adapted to wind saiddraft elements, and

optionally controlled power actuated means to cause rotation of eitheror both of said drums in a winding direction either simultaneously orseparately at either of two speeds or to cause the simultaneous rotationtuated means to cause rotation of either or both of id drums in awinding direction either simultaneously or separately at either of twospeeds or to cause the simultaneous rotation of the drums each at adifferent speed as and for the purpose set forth.

3. In a machine 0 the class described, the combination with a frameadapted to rest upon and slide in any direction over the floor of amine, of mining mechanism mounted thereon, feedin and guiding mechanismcomprising two, exible draft elements adapted to cooperate withanchoring devices external of the machine, and two similar winding drumsmounted for rotation about vertical axes and adapted to wind said draftelements, and optionally controlled power actuated means to causerotation of either or both of said drums in a winding direction eithersimultaneously or separately at either of two speeds or to cause thesimultaneous rotation of the drums each at a different speed as and forthe purpose set forth.

4. In a machine of the class described, the combination with a frameadapted to rest upon and slide in any direction over the floor of amine, of mining mechanism mounted thereon, feeding and guiding mechanismcomprising two flexible draft elements adapted to cooperatewithanchoring devices ex ternal of the machine, two winding drumsmounted for rotation about vertical axes and adapted to wind said draftelements and optionally controlled power actuated means to causerotation of either or both of said drums in a winding direction eithersimultaneously or separately or to cause the simultaneous rotation ofthe drums each at a different speed or to permit the free rotation ofeither or both of said drums as and for the purpose set forth.

5. In a machine of the class described, the combination with a frameadapted to rest upon and slide in any direction over the floor of amine, of mining mechanism mounted thereon, a motor for actuating saidmining mechanism, feeding and guiding mechanism comprising two flexibledraft elements adapted to cooperate with anchoring devices external ofthe machine, two winding drums mounted upon said frame for rotationabout vertical axes and adapted to wind said draft elements, anindependent planetary gearing associated with each of said drums andconnected with said motor, and means to optionally control saidplanetary gearings to cause rotation of either or both of said drums ina winding direction either simultaneously or separately at either of twospeeds or to permit their controlled rotation in the unwinding directionas and for the purpose set forth.

6. In a machine of the class described, the combination with a frameadapted to rest upon and slide in any direction over the floor of amine, of mining mechanism mounted thereon, a motor for actuating saidmining mechanism, feeding and guiding mechanism comprising two flexibledraft elements adapted to cooperate with anchoring devices external ofthe machine, two winding drums mounted upon said frame for rotationabout vertlcal axes and adapted to wind said draft elements, anindependent planetary gearing associated with each of said drums andconnected with said motor, means to optionally control said planetarygearings to cause rotation of either or both of said drums in a windingdirection either simultaneously or separately at either of two speeds orto per- I n1t their controlled rotation in an unwindmg direction, andmeans to permit free rotatlon of said drums as and for the purpose setforth.

7 In a machine of the class described, the combination with a frameadapted to rest upon and slide in any direction over the floor of amine, of mining mechanism mounted thereon, a motor for actuating themining mechanism, feeding and guiding mechanism comprising two flexibledraft elements adapted to cooperate with anchoring devices external ofthe machine, two winding drums mounted upon the frame for rotation aboutvertical axes symmetrically disposed in a transverse vertical plane oneat either side of the longitudinal center line of the machine andadapted to wind said draft elements, an independent planetary gearingassociated with each of said drums and connected with said motor, andmeans to optionally control said planetary gearings to cause rotation ofeither or both of said drums in a winding direction eithersimultaneously or separately at either of two speeds as and for thepurpose set forth.

8. In a machine'of the class described, the combination with a frameadapted to rest upon and slide in any direction over the floor of amine, of mining mechanism mounted thereon, a motor for actuating themining mechanism, feeding and guiding mechanism comprising two flexibledraft elements adapted to cooperate with anchoring devices external ofthe machine, two winding drums mounted upon the frame for rotation aboutvertical axes symmetricalh disposed in a transverse vertical plane oneat either side of the longitudinal center line of the machine andadapted to wind said draft element. an independent planetary gearingassociated with each of said drums and connected 'Wlvlll said motor,means to optionally control said planetary gearings to cause rotation ofeither or both of said drums in a winding direction eithersimultaneously or separately at either of two speeds, and devicespositioned at one side of the machine convenient to the hand of theoperator for the actuation of said controlling means as and for thepurpose set forth.

9. In a machine of the class described, the combination with a frameadapted to rest u on and slide in any direction over the floor of amine, of mining mechanism mounted thereon, a motor for actuating saidminng mechanism, feeding and guiding mechanism comprising two flexibledraft elements adapted to cooperate with anchoring devices external ofthe'machine, two winding drums mounted upon said frame for rotationabout vertical axes and adapted to wind said draft elements, gearingassociated with each of said drums and actuated by said motor, and meansto optionally control said gearing to cause rotation of either or bothof said drums in a winding direction either simultaneously or separatelyat either of two speeds or to cause the simultaneous rotation of thedrums each at a different speed or to permit their controlled rotationin an unwinding direction as and for the purpose set forth.

10. In a machine of the class described, the combination with a frameadapted to rest upon and slide in any direction over the floor of amine, of mining mechanism mounted thereon, a motor for actuating saidmining mechanism, feeding and guiding mechan sm comprising two flexibledraft elements adapted to cooperate with anchoring devices external ofthe machine, two winding drums mounted upon said frame for rotationabout vertical axes and adapted to wind said draft elements, gearingassociated with each of said drums and actuated by said motor, means tooptionally control said gearing to cause rotation of either or both ofsaid drums in a winding direction either simultaneously or separately ateither of two speeds or to cause the simultaneous rotation of the drumseach at a different speed or to permit their controlled rotatidn inunwinding direction, and means to permit free rotation of said drums asand for the purpose set forth.

11. In a machine of the class described, the' combination with a frameadapted to rest upon and slide in any direction over the floor of amine, of mining mechanism mounted thereon, a motor for actuating saidmining mechanism, feeding and guiding mechanism comprising two flexibledraft elements adapted to cooperate with anchoring devices external ofthe machine, two winding drums mounted upon said frame for rotationabout vertical axes and adapted to wind said draft elements, gearingassociated with each of said drums and actuated by said motor to causerotation of said drums in opposite direction, and means to optionallycontrol said gearing to cause rotation of either or both of said drumsat either of two speeds or to cause the simultaneous rotation of thedrums each at a different speed as and for the purpose set forth.

12. In a machine of the class described, the combination with a frame,of a horizontall disposed power actuated' shaft rotatably mounted insaid frame, a worm fixed to said shaft, two worm wheels mountedfor-rotation about vertical axes and engaging opposite sides of saidworm, a winding drum rotatable about a vertical axis positioned beneatheach of said worm wheels, a system of gearing above each of said wormwheels arranged to operatively connect the respective drums and wormwheels, and means to control each of said systems of gearing to causerotation of its drum at either of two speeds as and for the purpose setforth.

13. In a machine of the class described, the combination with a frame,of a horizontall disposed power actuated shaft rotatably mounted in saidframe, a worm fixed to said shaft, two worm wheels-mounted for rotationabout vertical axes and engaging opposite sides of said worm, a windingdrum rotatable about a vertical axis positioned beneath each of saidworm Wheels, a system of gearing above each of said worm wheels arrangedto operatively connect the respective drums and worm wheels, and meansto control each of said systems of gearing to cause rotation of itsdrums at either of two speeds or to permit its controlled rotation inthe opposite direction as and for the purpose set forth.

14. In a machine of the class described, a frame, a motor on said frame,a power transmitting shaft extending longitudinally of the frame, a pairof winding drums at the rear of said frame rotatable about vertical axessymmetrically disposed at either side of said shaft, a worm gearassociated with each of the drums and disposed on an axis parallel to aline parallel to the axis of its associated drum, driving connectionsbetween said gears and drums, and a worm on said shaft engaging each ofsaid gears.

15. In a machine of the class described, a. frame including a base plateforming supporting means for the rear of the frame, a motor on saidframe, a power transmission shaft extending longitudinally of the frame,a pair of winding drums rotatable immediately above said base plateabout vertical axes symmetrically disposed at either side of said shaft,a worm gear associated with and above each of the drums and disposed onan axis parallel to a line parallel to the axis of its associated drum,driving connections between said gears and drums, and a worm on saidshaft engaging each of said gears.

16. In a machine of the classdescribed, a frame, a motor on said frame,a power transmission shaft extending longitudinally of the frame, a pairof winding drums at the rear of the frame rotatable about vertical axessymmetrically disposed at either side of said shaft, a worm gearassociated with each of the drums and disposed on an axis parallel to aline parallel to the axis of its associated drum, planetary change speedgearings coaxially disposed relative to the worm gears and connectingthe respective gears and drums, and a worm on said shaft engaging saidgears.

17. In a machine of the class described, the combination with a singleworm, of two worm wheels in mesh with said worm and mounted for rotationon spaced-a art vertical axes, two rope drums mounted or rotation on twospaced-apart Vertical axes, variable speed power transmission mechanlsmbetween said worm wheels and said rope drums, and means for controllingsaid power-transmission mechanism'tovsecure variable speeds of rotationof either or both of said rope drums independently of each other.

18. In a machine of the class described, the combination with asupporting frame, of a motor thereon having a longitudinallyextendingarmature shaft, a worm on said shaft, worm gears on oppositesides of said worm with their axes vertical at the rear endportion ofthe frame, rope drums mounted at the rear end portion of the machine,and separate and independently controlled plural speed transmissionmechanisms between sa1d worm gears and said rope drums.

19. In a machine of the class described, the combination with asupporting frame, of two rope drums mounted thereon for rotation onvertical spaced-apart parallel axes, two variable speed powertransmission mechamsms one connected to one rope drum and the otherto-the other rope drum, and means for controlling said variable speedpower transmission mechanisms independently of each other to securerotation of either rope drum independently of the rotation of the otherrope 20. In a mining machine, the combination with a supporting, frameadapted to rest on and slide over the mine floor, of kerf-cuttingmechanism on the forward end of said frame, feedi and guiding mechanismon the rear end 0 said frame comprising rope drums mounted for rotationon vertical axes, a motor on said frame, and a single longitudinal shaftconnecting said motor to said cutting mechanism and extending to aposition between the axes of said rope drums for connection to thelatter.

21. In a low vein mining machine, the combination with a supportingframe, of kerfcutting mechanism connected to the forward end thereof,feeding and guiding mechanism comprising two rope drums mounted forrotation on vertical spaced-apart parallel axes on the rear end of saidframe, a motor mounted on said frame between the top and bottomsurfacesthereof, a central longitudinal motor shaft connected at itsforward end to said cutting mechanism and extending at its rear end to aposition between said vertical on the rear end of said frame andcomprising two rope drums mounted to rotate on vertical spaced-apartparallel axes, a motor on said v supporting frame, a driving connectionbetween said motor and said kerf-cutting mechanism, a worm connected tosaid motor to be driven thereby, two worm wheels meshin with said worm,and separate variable speed power transmission mechanisms one betweenone of said worm wheels and the feeding rope drum and the other betweenthe other worm wheel and the guiding rope drum.

23. In a low vein mining machine, the combination with a supportingframe, of cutting mechanism on the front end thereof, feeding andguiding mechanism on the rear end of said frame and comprising ropedrums mounted for rotation on vertical axes, a worm connected to saidmotor to be driven thereby, two worm wheels always in mesh with saidworm, and separate and independent variable speed power transmissionunits one connected between one of said worm wheels and the feeding ropedrum and the other connected between the other worm wheel and theguiding rope drum.

24. In a low vein mining machine, the combination with a supportingframe adapted to rest on and slide over a mine floor, of an elongatedchain kerf-cutter connected to the forward end of said frame, feedingand guiding mechanisms on the rear end of said frame and comprising tworope drums mounted for rotation on vertical axes, a motor on the framebetween the upper and lower surfaces thereof, a driving connectionbetween said motor and said chain kerf-cutter, a driving worm connectedto said motor and located at the rear end of said frame, two worm wheelsmeshing with said worm and mounted to rotate on vertical axes, and twoseparate and independent variable speed power transmission units oneconnected between one of said worm wheels and the feeding rope drum andthe other connected between the other worm wheel and the guiding ropedrum.

25. In a low vein mining machine, the combination with a supportingframe, of an elongated chain kerf-cutter on the forward end of saidframe, feeding and guiding mechanism s mmetrically arranged on the rearend of sai frame and comprising two rope drums mounted for rotation onparallel spacedapart vertical axes, a motor on said frame between the uper and lower surfaces thereof, a longitu inal central motor shaftconnected at its forward end to said kerf-cutter and extending at itsrear end to a position between said vertical axes, a worm on the rearend of said shaft, two worm wheels meshing with said worm andsymmetrically arranged to rotate on vertical spaced-apart parallel axes,and two separate and independent varible speed power transmission unitscoaxial respectively withthe vertical axes of said worm wheels and oneconnected between one worm wheel and the feeding rope drum and the otherconnected between the other worm wheel and the guiding rope drum.

26. In a mining machine, the combination with a frame adapted to rest onand slide over a mine floor, of cutting mechanism carried thereby, amotor connected to said cut ting mechanism to drive the same, andapparatus for eflecting sliding of said frame over the mine floorcomprising a feeding rope drum and a guiding rope drum, two plural speedtransmission units one connected to the feeding rope drum and the otherconnected to the guiding rope drum, separate and independent controllingmechanisms one associated with one of said units and the otherassociated with the other unit, and power transmission mechanismcomprisin a single pair of worm gear wheels connecte between said motorand said units.

27 In a mining machine, the combination with a frame, of cuttingmechanism carried thereby, a motor connected to said cutting mechanismto drive the same, and apparatus for feeding and guiding the machinecomprising a feed rope drum and a guide rope drum, a plural speedtransmission unit for the feed drum, a separate plural speedtransmission unit for the guide rope drum, mechanism for controlling theunit for the feed drum, separate mechanism for controlling the unit forthe guide drum, and power transmission mechanism having only one pair ofgear wheels one connected to one of said units and the other connectedto the other unit.

28. In a mining machine, the combination with a frame, of cuttingmechanism thereon, a motor connected to said cutting mechanism to drivethe same, feeding mechanism comprising rope drums rotatable on verticalaxes, and motor 0 erated means for driving said rope drums including afast and slow speed gear train for each rope drum and capable-of drivingonly the rope drum to which 1t is connected, all of the gears of saidgear trains rotating on vertical axes at either speed. v

29. In a mining machine, the combination with a frame, of cuttingmechanism carried thereby, a motor connected to said cutting mechanismto drive the same, feeding mechanism comprising rope drums rotatable onvertical axes, plural speed transmission mechanisms one for each ropedrum and each capable of driving only the rope drum to which it isconnected, said transmission mechanisms each having a fast and slowspeed gear train the initial and final gears of which are on fixed axes.

30. In a mining machine, the combination with a frame, of cuttingmechanism thereon, a motor for driving said cutting mechanism, feedingmechanism including rope drums rotatable on vertical axes and eachhaving a draft rope connected thereto and wound thereon and extendingtherefrom, motor operated means for said rope drums including a fast andslow speed gear transmission mechanism for each rope drum, the geartransmission mechanism connected to each rope drum not being capable ofdriving the other rope drum, the initial and final gears of eachtransmission mechanism rotating on fixed axes during drive at eitherspeed.

In testimony whereof I have hereunto set my hand.

NILS D. LEVIN.

